Interactive 3D Projection is Foggy At Best

fog proj

Have a projector and a smoke machine handy? You might want to give this fog projection thing a shot! It’s called the MisTable and it’s a three-dimensional playground for interactive manipulation of images.

It’s a project by Bristol Interaction and Graphics group of the University of Bristol, and it’s an interesting twist on 3D projection. They’ve created what they call the MisTable which features a smoke machine, “smoke screens”, and three projectors. What it results in is an interactive table for two people. The tabletop surface is a display, as is the see through fog in front of each person (the “fog screens”).

While it is fairly easy to understand and explain, there’s a handy diagram after the following break showing how the system works. Our question is, when are one of you guys or gals going to try making one?

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Using Non-Crappy Software With The Da Vinci Printer

davinci

The Da Vinci printer from XYZprinting is turning out to be one of the best buys in the world of cheap, consumer printers. Sure, it uses chipped filament, but that’s an easy fix for anyone who knows what a .hex file is. And yes, the Da Vinci host software is a mess of proprietary garbage with limited functionality, but [Mark] has figured out a way around that.

When [Mark] received his Da Vinci, he immediately started snooping around inside the printer’s guts, like any good tinkerer should. He found an SD card holding all the sample prints that ship with the printer, all in a convenient Gcode format. Inside these sample .STL files were all the calls you would expect – setting the temperature, changing the layer height, and all the other good stuff you’d find in any other RepRap.

With a little bit of modification to .STL files generated by any slicing program, [Mark] isn’t limited any more by the terrible host software that ships with the Da Vinci. Combine this with the ability to reset the chip inside the filament cartridge, and [Mark] has a printer at least as functional as any open hardware model.

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Measuring Frequency Response with an RTL-SDR Dongle and a Diode

[Hans] wanted to see the frequency response of a bandpass filter but didn’t have a lot of test equipment. Using an RTL-SDR dongle, some software and a quickly made noise generator, he still managed to get a rough idea of the filter’s characteristics.

How did he do it? He ‘simply’ measured his noise generator frequency characteristics with and without the bandpass filter connected to its output and then subtracted one curve with the other. As you can see in the diagram above, the noise generator is based around a zener diode operating at the reverse breakdown voltage. DC blocking is then done with a simple capacitor.

Given that a standard RTL-SDR dongle can only sample a 2-3MHz wide spectrum gap at a time, [Hans] used rtlsdr-scanner to sweep his region of interest. In his write-up, he also did a great job at describing the limitations of such an approach: for example, the dynamic range of the ADC is only 48dB.

Lego Robot Plays Games For You As You Sleep

robot

[Uli Kilian] — best known for solving 100 Rubik’s cubes during the 2011 London Marathon — got addicted to a free iPad game called Jurassic Park builder. Being the efficient man he is, he soon realized the game could be automated — after all, you just have to tap on dinosaurs every few minutes to earn in-game currency…

He’s using a Lego Technic set with an old iPad, and an Arduino connected to a Windows laptop. Wheels roll the iPad back and forth as the robot plays the game. The “finger” of the robot is wrapped in tin-foil and connected to a ground pin to simulate a human finger for the iPad. The article doesn’t explain how it works, but by looking at the robot it appears to just randomly tap away back and forth across the screen — which we guess works for this game?

He hasn’t played with Lego since he was 8, and only just learned about the Arduino a few weeks prior to building this. As a 3D artist he was intrigued to do something in the real-world — nice!

[Thanks Aurelio and William!]

Awww Shoot! My Spool Doesn’t Fit My Holder

spoolholder-main

The great thing about standards is that there are so many to choose from. Filament spools certainly do not deviate far from this sarcastic saying. So what are we 3D Printer folks to do? Here are a couple completely different DIY options:

[Mark] made a spool holder that can accept 2 different width spools. This design uses skate bearings to support the spool on two points at each end. There are 3 sets of bearing blocks to accommodate the 2 different width spools. When either size spool is installed, one of the bearing block sets goes unused.

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Hackaday Retro Edition: Parallel Port Ethernet

It’s time once again for a roundup of ancient hardware that has successfully loaded our retro edition. Up this time is a completely random and totally not planned roundup of parallel port to Ethernet adapters.


First up is [Tom Moss] with his IBM 5150 – the first ‘IBM Compatible’ home computer, progenitor of the i7 boxxen warming your ankles as you read this. This machine comes standard with a 4.77 MHz 8088 CPU, 8087 FPU, 512k RAM, two 360k 5.25″ floppy drives, and a few very cool additions: an ISA to CompactFlash card adapter, giving [Tom]‘s box 4GB of storage.

How is [Tom] connecting to the Internet? A Xircom PE3-10BT Network Adapter. This neat device turns any parallel port into an Ethernet. With a Telnet program, [Tom] was able to connect to a Unix system and use Lynx to browse over to the retro site. He’s yet to get a DOS browser working, but FTP is go, allowing him to download ancient software directly onto his huge CF card.

The next one isn’t exactly vintage, but it does carry the spirit of antiquated hardware onto the web. [Valentin] is using a FleaFPGA and a 186 over at OpenCores. The FPGA board gives him VGA output, an SD card, A PS/2 keyboard, but no options for networking. That’s no problem for [Valentin], as he wired up a Xircom PE3 parallel port to Ethernet adapter. Yes, the same adapter as the 5150 above. [Valentin] says his parallel port hack is a bit of a mess with non-bidirectional and no dedicated IRQ hardware support. It works, though, so we can’t fault him for that.

We’re always looking for people who have loaded our retro edition on old hardware. If you have some outdated hardware sitting in the attic, get it out, load up Hackaday Retro, and send it in.

Pics from [Tom] and [Valentin] below.

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Kyub MIDI Keyboard Puts a Piano in Your Pocket

[Keith Baxter] loves making electronic instruments. His latest vision has come to life as Kyub, an open-source MIDI keyboard. [Keith] has previously graced our site and cracked Popular Science with his servoelectric guitar.

[Keith] wanted to make a completely open source instrument that’s elegant, useful, and a bit more accessible than the servoelectric guitar, so he teamed up with a hacker/electronic music expert and an industrial designer. He built the early prototypes around an Arduino Uno. The current iteration uses a Teensy 2.0 and is available in various forms through Kickstarter. [Keith] opened the Kyub up to crowd funding in an effort to obtain volume pricing on some of the parts as well as an Eagle license to make the PCB files available commercially.

The Kyub has eleven pressure-sensitive capacitive keypads on five sides of the cube. The accelerometer can be used to vary note volume, bend the pitch, or whatever else you program it to do. Of course, you’ll need a computer with a synthesizer program, but [Keith] says it is compatible with most software synth programs, some of which are free.

There’s a demo video of an early prototype after the break. Videos of the Kyub in its current form are available on the Kickstarter page.

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